This invention relates to the use of certain 1-aminobenzocycloalkane compounds. More particularly it is concerned with various substituted 1,2,3,4-tetrahydro-1-naphthylamines, and their acid addition salts, which are useful as potentiating agents in combination therapy with the L-isomer of 3,4-dihydroxyphenylalanine (L-Dopa) in the treatment of Parkinson's Disease.
Parkinson's disease is a chronic neurological disorder characterized by tremor, rigidity of the limbs and poverty of movement (hypokinesia). In most patients, initial symptoms develop in the fifth or sixth decade of life and gradually progress, death usually occurring about 10 years after onset. Parkinson's disease is common, its estimated prevalence being 1 in 1,000 of the population.
Known causes of Parkinson's disease include viral infection (encephalitis lethargica), toxins (manganese, carbon monoxide), vascular disease (atherosclerosis) and drugs (phenothiazines, haloperidol, reserpine). In most cases, however, no cause can be identified. Pathological examination of the brain reveals widespread degenerative changes in the basal ganglia, particularly the substantia nigra and corpus striatum.
During the past decade a new approach to Parkinson's disease has evolved, culminating in the introduction of L-Dopa, a drug which is likely to have an important impact on future management of this syndrome (Calne, D. B. and M. Sandler, Nature 226, Apr. 4, 1970).
No drug is ideal, and L-dopa is no exception. A significant proportion of patients have to discontinue their treatment owing to unpleasant side effects, the most common being severe nausea and vomiting. A more serious side effect is postural hypotension, the inability to maintain a normal blood pressure while standing, which can result in fainting and giddiness and is dangerous under certain circumstances.